<?php
/**
 * Consent state, settings, GPC detection, and consent logging.
 */

if (!defined('ABSPATH')) {
    exit;
}

class TSAI_Compliance_Consent {

    const OPTION = 'tsai_compliance_settings';
    const COOKIE = 'tsai_consent';

    /**
     * Default settings. The category keys ('analytics', 'marketing') are the
     * values used in data-tsai-category="..." attributes on gated scripts.
     */
    public static function defaults() {
        return array(
            // 'optin'  = full consent banner + per-category script gating (required once
            //            you load analytics/marketing trackers).
            // 'notice' = slim dismissible notice, no gating (right when a site sets only
            //            functional cookies — comments, logins, saved preferences).
            'mode'               => 'notice',
            'notice_text'        => 'This site uses cookies that are necessary for it to function (comments, logins, and saved preferences). We do not use advertising or third-party tracking cookies.',
            'privacy_policy_url' => '',
            'do_not_sell_url'    => '', // optional; blank = use the preferences modal
            'banner_heading'     => 'We value your privacy',
            'banner_text'        => 'We use cookies to analyze traffic and improve your experience. You can accept all, reject non-essential cookies, or choose which categories to allow. Necessary cookies are always on.',
            'cookie_days'        => 180,
            'consent_version'    => 1,
            'enable_logging'     => 1,
            'categories'         => array(
                'analytics' => array(
                    'label'       => 'Analytics',
                    'description' => 'Helps us understand how visitors use the site (e.g. page views, traffic sources).',
                ),
                'marketing' => array(
                    'label'       => 'Marketing',
                    'description' => 'Used to personalize content and measure advertising.',
                ),
            ),
            // One external script per line, format: category|https://example.com/script.js
            'gated_scripts'      => '',
        );
    }

    public static function settings() {
        $saved = get_option(self::OPTION, array());
        if (!is_array($saved)) {
            $saved = array();
        }
        $s = wp_parse_args($saved, self::defaults());
        // categories must merge per-key so partial saves don't drop defaults
        if (empty($s['categories']) || !is_array($s['categories'])) {
            $s['categories'] = self::defaults()['categories'];
        }
        return $s;
    }

    public static function init() {
        add_action('rest_api_init', array(__CLASS__, 'register_routes'));
    }

    public static function activate() {
        self::create_table();
        if (get_option(self::OPTION) === false) {
            add_option(self::OPTION, self::defaults());
        }
    }

    /**
     * Global Privacy Control: a Sec-GPC: 1 request header is a legally
     * recognized opt-out signal under California's CPRA. When present we treat
     * all non-necessary categories as denied.
     */
    public static function is_gpc() {
        return isset($_SERVER['HTTP_SEC_GPC']) && $_SERVER['HTTP_SEC_GPC'] === '1';
    }

    /**
     * Returns the decoded consent cookie as an array, or null if absent/invalid.
     */
    public static function get_consent() {
        if (empty($_COOKIE[self::COOKIE])) {
            return null;
        }
        $raw = wp_unslash($_COOKIE[self::COOKIE]);
        $data = json_decode($raw, true);
        if (!is_array($data)) {
            return null;
        }
        return $data;
    }

    /**
     * Server-side check usable in PHP/templates:
     *   if (TSAI_Compliance_Consent::has_consent('analytics')) { ... }
     */
    public static function has_consent($category) {
        if ($category === 'necessary') {
            return true;
        }
        if (self::is_gpc()) {
            return false;
        }
        $c = self::get_consent();
        return $c && !empty($c[$category]);
    }

    /* ---------- Consent logging ---------- */

    public static function table_name() {
        global $wpdb;
        return $wpdb->prefix . 'tsai_consent_log';
    }

    public static function create_table() {
        global $wpdb;
        $table   = self::table_name();
        $charset = $wpdb->get_charset_collate();

        $sql = "CREATE TABLE $table (
            id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            consent_id VARCHAR(64) NOT NULL,
            categories TEXT NOT NULL,
            gpc TINYINT(1) NOT NULL DEFAULT 0,
            ip_hash CHAR(64) NOT NULL,
            user_agent VARCHAR(255) NOT NULL DEFAULT '',
            consent_version INT NOT NULL DEFAULT 1,
            created_at DATETIME NOT NULL,
            PRIMARY KEY  (id),
            KEY consent_id (consent_id)
        ) $charset;";

        require_once ABSPATH . 'wp-admin/includes/upgrade.php';
        dbDelta($sql);
    }

    public static function register_routes() {
        register_rest_route('tsai-compliance/v1', '/consent', array(
            'methods'             => 'POST',
            'callback'            => array(__CLASS__, 'record_consent'),
            'permission_callback' => '__return_true', // public: visitors record their own consent
        ));
    }

    public static function record_consent($request) {
        $s = self::settings();
        if (empty($s['enable_logging'])) {
            return new WP_REST_Response(array('logged' => false), 200);
        }

        global $wpdb;
        $params     = $request->get_json_params();
        $categories = isset($params['categories']) && is_array($params['categories']) ? $params['categories'] : array();
        $consent_id = isset($params['consent_id']) ? sanitize_text_field($params['consent_id']) : wp_generate_uuid4();

        // Hash the IP rather than storing it raw — it's a compliance tool, after all.
        $ip      = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '';
        $ip_hash = $ip ? hash('sha256', $ip . wp_salt()) : '';
        $ua      = isset($_SERVER['HTTP_USER_AGENT']) ? substr(sanitize_text_field(wp_unslash($_SERVER['HTTP_USER_AGENT'])), 0, 255) : '';

        $wpdb->insert(self::table_name(), array(
            'consent_id'      => substr($consent_id, 0, 64),
            'categories'      => wp_json_encode($categories),
            'gpc'             => self::is_gpc() ? 1 : 0,
            'ip_hash'         => $ip_hash,
            'user_agent'      => $ua,
            'consent_version' => intval($s['consent_version']),
            'created_at'      => current_time('mysql', true),
        ));

        return new WP_REST_Response(array('logged' => true, 'consent_id' => $consent_id), 200);
    }
}